Afghan officials agree that opium poppy cultivation is among the biggest problems facing the country, but many differ on how to tackle it. The World Bank says solving the problem will take both development aid and better policing.

If there is anything all the candidates in Afghanistan's recent presidential election can agree on, it is the need to stamp out opium production.

In addition to being a social menace - contributing to crime and problems with drug addiction - the opium trade helps support semi-independent militia commanders seeking to undermine the central government.

But senior World Bank advisor William Byrd, the lead author of a recent report on the Afghan economy, says opium cultivation will be one of the most difficult issues for the country to solve.

"The poppy economy in Afghanistan is unique, in that it accounts for about a third of the total national economic activity," said Mr. Byrd. "No other country that I'm aware of is at even more than 10 percent."

Some success in the opium war came during the previous Taleban regime. The strict Islamic government used tough enforcement practices to bring poppy cultivation down to almost zero in the areas of the country it controlled.

But Mr. Byrd says the Taleban's emphasis on enforcement would not have solved the problem forever. He notes that poor tenant farmers would likely have returned to growing opium to pay off debts to their drug-trafficking sponsors.

"Pressures were building up enormously," he said. "I mean, let's not forget the Taleban banned production, [but] they did not ban the trade and they did not ban the opium debts."

The post-Taleban transitional government tried to pay off these farmers in exchange for destroying their opium crops, but Mr. Byrd says this approach failed, too. "The signal it sends is that, well, if you grow poppy, your field is destroyed but you're going to get compensated," he said.

A successful campaign against the opium economy, he says, will need to combine strong law enforcement with relief for indebted farmers to be truly effective and lasting.

Doing one without the other, he says, will only offer a temporary solution.